Tomcat is a web container so its good for the SCWCD, where you play around with servlets and jsp. But for SCBCD you need an application server, which has both a web container and an EJB container, you could go with the Sun Application server. We have other application servers like JBOSS, WebSphere and WebLogic.
You might want to try this tutorial to get a better understanding of EJB's. [ July 27, 2005: Message edited by: Abdulla Mamuwala ]
if you pick up the Headfirst book, they help you build your first app. step by step and this forum would help you in case you run into any glitches. But this book would start you on your way. And by the way they suggest practice RI server with J2EE 1.3. And you can then download the help/ errors and sharpen files from the publishers site. I hope I am being helpful here!